A schematic of TerraPower's proposed Natrium nuclear power plant. (TerraPower)

The fate of TerraPower’s proposed Natrium nuclear power plant in Kemmerer may now depend on how quickly the federal government can “downblend” enough weapons-grade uranium, then help stand up a new U.S.-based commercial supply of high-assay, low-enriched uranium (HALEU) fuel.

Global events have interrupted fuel supplies. But falling short of the scheduled 2028 in-service date could jeopardize $2 billion in federal funding from the U.S. Department of Energy — half the estimated $4 billion cost of the liquid sodium-cooled nuclear power plant — and could scuttle the entire project, according to TerraPower. Blowing the now-tenuous deadline could also cast a shadow over TerraPower’s vision to deploy more Natrium power reactors in Wyoming and across the globe.

“A reactor that doesn’t have access to fuel is not a particularly useful piece of equipment,” TerraPower Director of External Affairs Jeff Navin said.

Fuel switch

Nine months after selecting Wyoming for its pilot Natrium reactor in 2021, TerraPower cut ties with the Russian state-owned Tenex — the only facility in the world with the capacity to supply commercial volumes of HALEU — after Russia invaded Ukraine. At least one other “advanced nuclear” power demonstration project may also hinge on how quickly the U.S. can accelerate a domestic HALEU fuel supply: X-energy in Washington state. 

TerraPower CEO Chris Levesque visits with Lincoln County residents Jan. 19, 2022 in Kemmerer. (Dustin Bleizeffer/WyoFile)

Despite the logistic and scheduling challenges, TerraPower is moving forward as planned, according to the company. The nation’s electric power sector is moving swiftly to choose future power resources, and TerraPower sees a narrow window of opportunity to ensure advanced nuclear reactors play a major role, according to the company’s spokesperson.

“Utilities, states, countries and others are making decisions about what their [electric] generation is going to look like in the 2030s, and if we aren’t commercially available by then it’s going to hurt our ability to sell subsequent reactors,” Navin said.

Wyoming officials hailed the Natrium demonstration project in Kemmerer, and potentially more Natrium reactors in the state, as an economic bridge to help backfill gaps left by a declining coal-fired power industry. 

TerraPower selected Kemmerer and PacifiCorp’s nearby Naughton coal-fired power plant as the location for the Natrium reactor demonstration plant so it could re-purpose infrastructure that might otherwise be abandoned. The Naughton coal plant is scheduled to be decommissioned in 2028.

The Naughton coal-fired power plant, pictured Jan. 19, 2022, will be retired in 2028 when TerraPower commences operations for its proposed Natrium nuclear reactor power plant at the same location. (Dustin Bleizeffer/WyoFile)

TerraPower, co-founded and backed by Microsoft billionaire Bill Gates, plans to begin operations in 2028 then pass ownership of the nuclear power plant to PacifiCorp. However, some doubt the feasibility of the ambitious schedule. The Oregon Public Utility Commission in March declined to formally acknowledge PacifiCorp’s plans for Natrium to be a part of its future electrical generation portfolio.

Scramble for U.S. fuel supply

TerraPower and other developers hoping to build the next generation of nuclear power facilities in the U.S. were already working with Congress and the Department of Energy to expand the nation’s commercial HALEU supply chain before Russia’s war in Ukraine.

TerraPower Director of External Affairs Jeff Navin in Kemmerer Jan. 19, 2022. (Dustin Bleizeffer/WyoFile)

Natrium, and other advanced nuclear reactor designs, require HALEU fuel, which is enriched to nearly 20% with uranium-235 compared to the 5% that makes up most of the fuel that powers the nation’s legacy reactors. Two facilities in the U.S. have HALEU fuel enrichment capabilities, but neither have the capacity to provide enough of the fuel for even one Natrium power plant, according to TerraPower.

Congress authorized the HALEU Availability Program in 2020 and eventually appropriated $45 million to “expedite” HALEU fuel-processing capacity in the U.S. The Inflation Reduction Act, which Wyoming’s entire congressional delegation voted against, added another $700 million toward the effort.

The federal support will go a long way to attract private investment and establish a reliable, commercial supply of HALEU in the U.S., perhaps in time to meet the 2028 in-service deadline in Kemmerer, Navin said. But the Natrium reactor will require an initial “core load” fuel delivery in 2025. TerraPower is now imploring federal officials to downblend enough weapons-grade uranium to meet that timeline.

“The only way we can meet the timeline that we laid out is to look for alternative [HALEU] sources,” Navin said. “And the most likely place that we can get those alternative sources is going to be governments — largely the U.S. government — that can make material available to be downblended.”


Nuclear weapons-grade uranium is enriched to about 93% U-235. It can be blended with lower potency uranium to meet nuclear power reactor specifications. Combined, TerraPower’s Natrium and X-energy’s Xe-100 demonstration projects could require about 20 metric tons of HALEU derived from downblending, Navin estimated.

The Bill Gates-backed TerraPower plans to build the experimental Natrium liquid sodium-cooled nuclear reactor power plant just outside Kemmerer. (Google Earth image)

“To stay on schedule, we need about 5 metric tons delivered by the end of 2025,” Navin said. “That’s our first real deadline.”

Both the U.S. government and TerraPower are helping fund efforts to expand the HALEU fuel enrichment facility in Ohio owned by Centrus Energy Corp. The facility will begin producing just shy of 1 metric ton of HALEU annually in 2023. 

“We’re not going to find all of our supply for our first core load from one source. We’re going to have to cobble together multiple pieces in order to stay on the schedule,” Navin said, adding it’s unclear how much weapons-grade uranium can be processed into HALEU or how quickly.  “We’re all looking around at our options to see what materials available and how we can treat that material to maximize the amount of HALEU.”

Dustin Bleizeffer is a Report for America Corps member covering energy and climate at WyoFile. He has worked as a coal miner, an oilfield mechanic, and for 25 years as a statewide reporter and editor primarily...

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  1. The United States doesn’t need to maintain a supply of weapons grade uranium because it isn’t used in the fission-fusion-fission warheads that populate the nuclear arsenal that uses plutonium in the “triggers” and tritium in the fusion section thereof.

  2. To answer Dewey’s question about radioactive waste, these systems are far more efficient than the old LWR systems. What used to require containment for 300,000 years now only needs limited containment shelf life of 300 years. The ability to “clean” the sodium of radioactive waste versus water is a very compelling facet of MSRs. I’d encourage learning more before asking questions that are clearly posed as “roadblocks.”

  3. Based upon my research this is a very promising technology to provide for our country’s energy needs in the future. We need to do our part to ensure a planet that will sustain human systems through reduced carbon emissions. But we also need to provide sustainable power that will not be subject to the whims of the wind or availability of sunlight. I applaud the TerraPower initiative and look forward to seeing this technology at work.

  4. Bill Gates’ net worth is estimated at $102.5 billion. And yet his TerraPower vanity venture is going after subsidies. This is, of course, in line with the history of the entire nuclear power enterprise, which has never been able to stand up on its own two financial feet and is now unable to compete with cleaner, safer, increasingly cheaper renewables and energy efficiency solutions.

  5. Fuel or no fuel, why is anyone considering a baseload water-evaporating power plant in the Colo River Basin in a state which could generate all it’s own power and export plenty with wind and a bit of solar? Instead of the DOE’s new C2N (Coal-To-Nuclear) program, C2S (Coal-To-Storage) should be promoted. Today, electricity storage is available at the cost of nuclear in the future. And those storage costs are going down. From batteries using iron-air, iron-flow, sodium, aluminum etc. to compressed or cooled/heated stored gases which utilize compressors and turbines and other power plant skills. These systems change variable renewable power to dispatchable power. Expensive nuclear power should be saved for land-short places like Connecticut, or energy-dense areas like the Gulf Coast.

    1. $4B for 350MW? That’s nuts. $4B would buy 4000MW of utility scale solar, more than 10x what’s being planned here using “shovel read” technology with virtually no maintenance, safety hazard, security risk, or hazardous waste. Existing hydro, only run at night, can keep the lights on until pump storage and aluminum – sulfur batteries come on line. Nuclear just doesn’t add up. https://www.solarreviews.com/blog/what-is-a-solar-farm-do-i-need-one

      1. In response to David Nix. David’s statements are littered with inaccurate statements. Solar is not always shovel ready. The infrastructure such as transmission lines being readily available is a very important consideration. That is where his argument fails. Transmission lines being readily available for a 4000 MW solar farm is not true.

        Also you need 20–50 km2/GWh according to https://www.nrel.gov/docs/fy04osti/35097.pdf. That would be close to 35000 acres needed for a solar farm needed to produce 4000MW of intermittent energy. This does not take into account that the sun does not shine for 24 hrs so this type of energy source is not base load.

        Then he goes on relying on an unknown such as “when battery storage comes in line.” That is a huge assumption. We are not close to storing energy that can produce 4000MW that can be considered a base load.

        Then he states solar has virtually no hazardous waste. Incorrect. Solar panel waste include heavy metals such as silver, lead, arsenic and cadmium. Recycling is much more expensive then just fabricating new solar panels. So if these panels are placed in a landfill, there exists possibility of these metals leaching out into groundwater.

        Advanced reactor technologies takes into account nuclear waste. See https://www.terrapower.com/natrium-program-summary/ for a discussion on waste and safety.

        We need a mix of all types of energy sources.

        1. Well said sir! Absolutely, a mosaic of electrical sources is necessary. Maximum energy density with minimum carbon impact should be the goal. That won’t be achieved through solar and wind alone.

    2. In response to Fred Porter, the reason why it is being sited in Wyoming is very straightforward. Here is what is posted on TerraPower website. “The demonstration project team evaluated a variety of factors when selecting the site of the Naughton Power Plant, where the remaining two coal units are scheduled to retire in 2025. Factors included community support, the physical characteristics of the site, the ability of the site to obtain a license from the Nuclear Regulatory Commission (NRC), access to existing infrastructure, and the needs of the grid.” Access to infrastructure also means a workforce. The personnel working at the coal site will be trained to work at this site. Having worked in the nuclear power industry for 35 years, the training of coal personnel to operate such a plant can be accomplished. Now in regards to your statement that batteries can be used to store the energy and costs are going down is only partially true. The storage capacity to supply power to industry and widespread homes is not available at the level that is needed. It would be great to place nuclear in Connecticut or Gulf Coast but once again TerraPower did an exhaustive survey and Wyoming is the best place for this demonstration plant. After this plant is successfully demonstrated, there will be deployment of additional plans to other locations.

  6. Does this have anything to do Hillary Clinton when she was Sec of State and sold-gave Russia the rights to our uranium?

  7. There was an additional $750 million of funding recently committed that was led by SK Inc. out of South Korea which should help solidify the completion. I’m not certain why the US Department of Energy, of which Centrus CEO Daniel Poneman was a former director, couldn’t extend the 2028 in service date. Although, maybe that would require an act of Congress and isn’t something the Department of Energy controls. Would like some more information on that.

  8. We are going to build a power plant that depends on RUSSIA for fuel? Maybe we should ask Europe how well that has worked out for them.

  9. A couple of points.

    1. Natrium’s use of the phrase “cobbled together” to describe sourcing enough fuel to put the plant into operation does not enhance public confidence in the success of the project.

    2. “De-enriching” weapons grade uranium to the level required for the plant is not the first problem Natrium faces. The main problem is that weapons grade uranium is destined for nuclear weapons. Especially given the current world situation and the threats posed by Russia and China, I think it highly unlikely the US government will accede to Natrium’s request and “de-enrich” already highly enriched uranium.

    Perhaps Dustin Bleizeffer can address this latter problem in a future article and explain how “blending” and “downgrading” work physically–particularly, how difficult is it?–as well as the government’s position on reducing its stockpile of weapons grade uranium just to get Natrium out of a jam.

    1. In 2019, the U.S. and Russia possessed a comparable number of nuclear warheads; together, these two nations possess more than 90% of the world’s nuclear weapons stockpile. As of 2020, the United States had a stockpile of 3,750 active and inactive nuclear warheads plus approximately 2,000 warheads retired and awaiting dismantlement. Of the stockpiled warheads, the U.S. stated in its March 2019 New START declaration that 1,365 were deployed on 656 ICBMs, SLBMs, and strategic bombers. It would seem that there are still enough nuclear weapons in our and Russia’s stockpiles to destroy the world several times over.